When a person is blind or has significantly impaired vision it is a struggle for that person to read and write. Braille, a system that uses a set of raised dots that correspond to the letters of an alphabet, is designed to alleviate this struggle by allowing people to read and write by touch. Braille is read by moving the hand or hands from left to right along each line. Both hands are generally involved in the reading process, and the reading itself is typically accomplished with the index fingers. On average people can read Braille about 125 words per minute, but greater speeds are possible if the person is well trained at reading this way.
The entire Braille alphabet is based on a six-dot cell. As FIG. 1a illustrates, the six-dots of a Braille cell are arranged and numbered 1-6. In the simplest form of Braille (called grade 1) a certain arrangement of dots within each cell stands for one letter. The English alphabet a through z is represented in the manner depicted in FIG. 1b. Braille also contains equivalents for punctuation marks and provides symbols to show letter groupings (see e.g., FIG. 1c). A cell containing a single dot 6 is used before each letter that is to be capitalized. The number sign, dots 3, 4, 5, 6, placed before the characters a through j makes the number 1 through 0. For example, a preceded by the number sign is 1, b is 2, etc.
Various other methods had been attempted over the years to enable blind people to read, many of them raised versions of print letters. It is generally accepted that the Braille system has succeeded because it is based on a rational sequence of signs devised for the fingertips, rather than imitating signs devised for the eyes. In addition, Braille can be written by blind people and can be used for any notation that follows an accepted sequence, such as numerals, musical notes or chemical tables. Thus, Braille is widely regarded as the standard way to communicate with the visually impaired.
To make it easier for visually impaired persons to interact with a particular device the manufacturers of these devices sometimes provide a set of instructions for using the device written in Braille. For instance, in addition to containing a regular printed set of instructions, it is commonplace for Automated Teller Machines (ATM) to contain a separate set of Braille instructions along side the printed instructions. In addition, the keyboard of the ATM machine may contain tactile queues (e.g., a raised portion indicative of the center key or some other combination of keys). These tactile queues are designed to further assist the visually impaired user by providing an indication of proper hand placement. Other devices adapted to assist visually impaired users are similarly configured in that the primary interface of printed characters exists separate from the interface for the visually impaired.
A problem encountered when attempting to add a Braille interface to an interface containing a set of alphanumeric characters is that two interfaces are required. A Braille interface for the visually impaired and an alphanumeric interface for the non-visually impaired. As FIGS. 1b and 1c illustrate, these two interfaces do not cohesively mesh with one another. The alphanumeric characters do not consistently cover the dots used to represent the Braille characters. Thus, any interface that utilizes both systems appears busy and contains redundant information. Because of these and other limitations there is a need for a solution that solves the problem of duplicity by unifying the interface for the visually impaired with the interface for the non-visually impaired.